Most of us think that when we stop talking, texting or surfing on our smartphones, the gadgets stop communicating. But research for Channel 4 News has revealed the hundreds of thousands of messages the phones send out every day, without us even knowing.

Some of these messages are useful – they help our phones and apps stay connected and up-to-date. But some are giving away our location and our phones’ unique identities to advertisers, who then use this information to target us.

As part of the Data Baby project, Channel 4 News has created a fake, virtual identity, and is tracking its data. And we decided to tap into the secret life of her mobile phone, listening in to the stream of information flowing to and from the devices with which many of us spend our entire day.

Along with the pre-installed apps, we downloaded over 30 of the most popular android phone apps, that have been installed over 100 million times: everything from WhatsApp messenger and Candy Crush Saga, to Google Translate and Skype.

Technology security firm MWR Infosecurity then created a special device to intercept all of the Data Baby’s phone communication.

We found that in an average 24 hour period, it sent out more than 144,000 “packets” of information. These tiny, one-line communications flowed to and from more than 315 computer servers around the world. Some contained the images and text that form web pages, for example. But others contained the exact location of the phone, right down to the postcode.

Main findings> In 24 hours the Data Baby phone made around 350,000 requests to 315 different servers> The phone’s location was sent six times to advertising firms in the US and Ukraine.> Even when idle for 45 mins, the phone still made 30,000 requests to 76 servers.> The phone’s unique ID was sent a dozen times, including when the phone was idle. Most of those communications were down to Talking Tom, a free cartoon app that has been downloaded over 190 million times.

Map above: the number of countries the Data Baby phone is communicating with when active

In several instances we found the phone’s location was sent to zigi.com – an advertising company based in the US and the Ukraine.

Talking Tom, a cartoon app that’s been downloaded more than 190 million times, sent the phone’s unique identifier (its IMEI) to an advertising agency called mopub.com.

Advertisers use this information – along with details of the model of phone and type of web browser being used – to target advertising. But many people whose information is sent have no idea it’s happening.

Your phone always has an internet connection, and so the applications, if they choose to, can continue communicating after you’ve put it down– Rob Miller

IT security consultant at MWR, Rob Miller, said: “In cases where you’re connecting to Facebook, obviously it’s going to be sending out the kind of info you then see as a user. But what we also saw was advertising networks sending some personal info – things like you’re actual location at the time, or in this case, your unique identifier for your phone: your IMEI number.”

Even when we’re not using our phones, they are still sending and receiving data. MWR’s kit counted 35,000 packets flowing in and out of the phone in just 45 minutes when it wasn’t in use (see map below).

Map above: the number of countries the Data Baby phone communicated with in the three hours it was idle

As the phone sat, apparently silent, contacts were in fact being made with 76 different servers around the world, in countries from the US to Europe to China and Singapore.

Mr Miller said: “the interesting thing is, and (it) might be surprising to a lot of people is, that (the) phone is always active. It always has an internet connection, and so the applications, if they choose to, can continue communicating after you’ve put it down.”

When mobile phones first became popular, they were mainly used for calls and texts, with limited internet ability. But over the last few years their reach has changed; now connected both via the mobile network and wifi, they are always online. Apps, too have transformed the secret life of the phone; unless switched off they are constantly running in the background, sending and receiving data.

This data, of course, ends up somewhere, and according to Channel 4 News research, it is advertisers who are the main recipients.